SIST EN 13192:2002

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zerstörungsfreie Prüfung - Dichtheitsprüfung - Kalibrieren von Referenzlecks für GaseEssais non destructifs - Contrôle d'étanchéité - Etalonnage des fuites de référence des gazNon destructive testing - Leak testing - Calibration of reference leaks for gases19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN 13192:2001SIST EN 13192:2002en01-junij-2002SIST EN 13192:2002SLOVENSKI
STANDARD



SIST EN 13192:2002



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13192November 2001ICS 19.100English versionNon destructive testing - Leak testing - Calibration of referenceleaks for gasesEssais non destructifs - Contrôle d'étanchéité - Etalonnagedes fuites de référence des gazZerstörungsfreie Prüfung - Dichtheitsprüfung - Kalibrierenvon Referenzlecks für GaseThis European Standard was approved by CEN on 10 October 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13192:2001 ESIST EN 13192:2002



EN 13192:2001 (E)2ContentspageForeword.31Scope.42Normative references.43Terms and definitions.44Classification of leaks.54.1Permeation leak.54.2Conductance leaks.55Apparatus.55.1Mass Spectrometer Leak Detector (MSLD), for methods A and B (see clause 6).55.2Capillary measurement tube equipment for method C (see clause 7).56Calibration by comparison (methods A and B).66.1Preparation of leaks and apparatus.66.2Measurement.67Calibration by direct flow measurement (method C).77.1Preparation of leaks and apparatus.77.2Measurement.88Results.118.1Evaluation for methods A and B (Comparison).118.2Evaluation for Method C (direct flow measurement).149Report.1510Labelling of reference leaks.1511Handling of reference leaks.1511.1Permeation leaks
(normally with reservoir fitted the leak outlet).1511.2Conductance leaks (normally without reservoir).15Annex A
(informative)
Calculation of leakage rate decrease due to tracer gas depletion in the reservoir.16Bibliography.17SIST EN 13192:2002



EN 13192:2001 (E)3ForewordThis European Standard has been prepared by Technical Committee CEN/TC 138 "Non-destructive testing", thesecretariat of which is held by AFNOR.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by May 2002, and conflicting national standards shall be withdrawn at the latest byMay 2002.This European Standard has been prepared under a mandate given to CEN by the European Commission and theEuropean Free Trade Association. This European Standard is considered to be a supporting standard to thoseapplication and product standards which in themselves support an essential safety requirement of a New ApproachDirective and which make normative reference to this European Standard.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,Switzerland and the United Kingdom.SIST EN 13192:2002



EN 13192:2001 (E)41ScopeThis draft European Standard specifies the calibration of those leaks that are used for the adjustment of leakdetectors for the determination of leakage rate in everyday use. The preferred calibration method in this case is acomparison with a standard leak. In this way the leaks used for routine use become traceable to a primary standardas the ISO 9000 series of standards require.The comparison procedures are preferably applicable to helium leaks, because this test gas can be selectivelymeasured by a mass spectrometer leak detector (MSLD) (the definition of MLSD is given in EN 1330-8).Calibration by comparison (see methods A and B below) with known standard leaks is easily possible for leaks withreservoir and leakage rates below 10-7Pa·m3/s.From 10-7 Pa·m3/s to 10-4 Pa·m3/s no leaks reliable enough to be used as transfer standard exist. Leaks in thisrange can only be calibrated by measurement of flow in a calibrated capillary tube (see method C below).Leakage rates greater than 10-4 Pa·m3/s can be measured by flow meters calibrated against primary nationalstandards.2Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 1330-8, Non-destructive testing - Terminology - Part 8: Terms used in leak tightness testing.EN 13625, Non-destructive testing - Leak test - Guide to the selection of instrumentation for the measurement ofgas leakage.3Terms and definitionsFor the purposes of this European Standard, the terms and definitions given in EN 1330-8 and the following apply.3.1unknown leakleak having a stable and repeatable leakage rate of known order of magnitude that can be determined by calibration3.2calibration of a reference leakset of operations which establish, under specified conditions, the relationship between leakage rate valuesrepresented by an unknown leak and the corresponding known values of the leakage rate by general definition in:"International vocabulary of basic and general terms in metrology"NOTE 1In the case of calibration by comparison, the known values of the leakage rate are represented by a standard leak.NOTE 2Normally, the result of a calibration is given as the leakage rate value for the reference leak.For proper usage of the different definitions of leakage rate, the following should be carefully considered:In leak detection, leakage rates are commonly given in units of pV-throughput (Pa·m3/s, mbar l/s). These are only a precisemeasure of gas flow if the temperature is given and kept constant.Flow units such as mass flow (g/y) or molar flow (mol/s) are sometimes used to overcome this problem.SIST EN 13192:2002



EN 13192:2001 (E)54Classification of leaks4.1Permeation leakThis type of leak is normally made with a tracer gas reservoir. It has the best long-term stability but an appreciabletemperature coefficient (approximately 3,5 %/K). Typical leakage rates are in the range from 10-10 Pa·m3/s to 10-4Pa·m3/s.4.2Conductance leaks4.2.1Capillary leakThis type of leak is available with or without a tracer gas reservoir. It has a low temperature coefficient(approximately 0,3 %/K) but easily blocks if not handled with care.
Typical leakage rates are greater than10-7 Pa·m3/s4.2.2Aperture leak (orifice)Orifice leaks are seldom used in practice, as they are difficult to manufacture and even more prone to blocking thancapillaries.4.2.3Compressed powder leakThis type of leak uses metal powder compressed into a tube. They are usually offered without reservoir. They areused for routine check of the sensitivity of leak detectors but they are not stable enough to be used as calibrationleaks.5Apparatus5.1Mass Spectrometer Leak Detector (MSLD), for methods A and B (see clause 6)To calibrate a leak by comparison to a known standard according to methods A and B described in clause 6, amass spectrometer leak detector is necessary as the transfer device. Such a leak detector shall fulfil the minimumrequirements for the measurement of leakage rate, laid down in EN 13625.The test port of the leak detector shall be equipped with an inlet system consisting of a set of ports with valves(preferably all metal) to couple the standard leak and the unknown leaks to the detection system and to shut off theleaks individually.The leak tightness of the inlet system shall be checked to a suitable level before a calibration is performed so thatambient tracer (e.g. helium of ambient atmospheric air) will not affect the measurement.5.2Capillary measurement tube equipment for method C (see clause 7)To calibrate a leak by measurement of capillary flow according to method C described in clause 7, a calibratedglass capillary tube (preferably with a suitable vent valve at one end, see Figure1) is necessary.An indicator fluid (normally water with some surfactant added or special oils) is used to produce the measurementslug in the capillary.To measure the time of slug movement, a timer or stopwatch will be needed. Instruments based on the timedmovements of a film in a tube are also available, e.g. a bubble flow meter.As conductance leaks normally have no tracer gas reservoir, a separate tracer gas supply is needed or calibrationmay be performed with filtered atmospheric air.SIST EN 13192:2002



EN 13192:2001 (E)66Calibration by comparison (methods A and B)There are two ways of calibrating leaks by comparison with known standard leaks. Both methods require theknowledge of the order of magnitude of the leakage rate to be measured. The methods differ in using one or twostandard leaks, resulting in different uncertainties of measurement. In the following, the two methods aredesignated as A and B:Method A:Comparison to one standard leak normally with a leakage rate of the same order of magnitudeMethod B:Comparison to two standard leaks with leakage rates normally lying on either side of the unknownleakage rateMethod A is most suitable for use on site as only one standard leak is used.
It is generally applicable but is mostreliable when the leakage rate of the unknown is close to that of the standard leak. This is because themeasurement uncertainty is directly dependent on the linearity of the leak detector in use. (See 8.1.2.2). As thelinearity error cannot be measured independently, it has to be estimated.
To keep the linearity error small, theoperating characteristics of leak detector should not change during calibration (e.g. automatic ranging should bedisabled).For more precise calibrations, where a definite measure of uncertainty is required or if a standard leak with aleakage rate close to the unknown is not available method B should be used.
By the use of two reference leaks, thenon-linearity of the leak detector is accounted for (see 8.1.2.3).6.1Preparation of leaks and apparatus6.1.1Warm-up of leak detectorThe leak detector used as a transfer device shall be set up according to the manufacturer's manual. The warm-uptime shall be at least 2 h.6.1.2Temperature accommodationThe unknown leak and the standard leak(s) for the comparison shall be stored in the same room where the test isto be carried out for at least 12 h to allow for temperature equilibration (an air-conditioned room is not necessary ifthere are no rapid temperature changes. Because of temperature fluctuations, an air-conditioning system can evenincrease the measurement uncertainty). The leaks shall be pumped out during the phase of thermalaccommodation. After temperature accommodation, to prevent any temperature changes during measurement,thermally insulating hoods (made of plastic foam or similar material) should be put over the leaks.6.1.3Connection to the leak detectorThe standard and unknown leaks are connected to the inlet system of the MSLD after temperature accommodationand pumped with their valves (if any) open for at least 30 min to remove any tracer gas that may have accumulatedin seals or valves. For the calibration of more than one leak, a separate pumping system and set of valves is usefulto keep all the leaks pumped until they are measured.6.2Measurement6.2.1Set-upThe leak detector is adjusted so that the major of the used leaks gives approximately a full-scale indication. It isimportant to ensure that the effective pumping speed is not changed during the measurements. If possible, eitherwith the leak detector or in an auxiliary device a long averaging time may be used to decrease the statisticalmeasurement uncertainty. Further a recorder taking data over some time can be used for that purpose. All thosemeasurement instruments should be used in such a way that they give nearly full-scale deflections for the biggestleak.6.2.2General measurement sequenceGenerally, each reading shall be obtained under steady flow conditions constant signal from the MLS
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